Less powerful chargers could be enough for many EV drivers, U of C study says

A common perception among electric vehicle drivers is that more powerful and costly chargers are needed in their homes to keep their cars running. But a report from the University of Calgary's School of Public Policy this week is challenging that notion, finding that slower, more accessible chargers would be effective for many drivers.

U of C associate professor of economics Blake Shaffer noted that he, like a lot of other EV drivers, believed his car required a 240-volt, or Level 2, charger in his home.

Installing those chargers can often require installing new wiring or an upgraded electric panel, and the power they require can put a strain on electric grids.

"The interesting thing we found here is most folks expect you need to install a fast charger at home, these Level 2 chargers, and we found that overwhelmingly you don't," Shaffer said.

He said the research he and his co-authors conducted found that a slower 120-volt or Level 1 charger — which uses more common household electrical sockets — is enough for the needs of most EV drivers.

Level 2 options are faster, with an average charging time of 55 minutes for a typical charging session, which Shaffer notes commonly begins when battery power reaches about 60 per cent. They also usually draw more power than large household appliances like ovens, air conditioners or dryers. So too many EVs charging at once in the same area can lead to greater strain on electrical distribution.

By contrast, Level 1 chargers need 10 to 12 hours to put the same amount of energy in a car during a typical charging session, but draw less power and are more widely available in homes.

Shaffer and his co-authors worked with Enmax to study data from the driving and parking habits of 129 EVs in Calgary between December 2021 and 2022. The study concluded that the distances these EVs traveled each day were short enough, and the time they were left parked each night long enough, that a Level 1 charger met the needs for 29 per cent of cars in the study.

An additional 53 per cent would have only needed to visit a public rapid charging station once per month or less on top of the Level 1 charging. 

'Costly to have to go to Level 2'

"It's costly to have to go Level 2. It's costly for the individual, but it will be costly for distribution networks," Shaffer said.

"If everyone goes level 2, there will be significant upgrades required to distribution networks, and to me, that's where the real challenge of EVs comes about."

More education on how accessible home charging can be, paired with more public chargers to top cars up when needed, could encourage more uptake of EVs.

He added that lower-power Level 2 charges could also be promoted for homes where drivers travel long distances with less time parked at home.

EV usage in Alberta is rising, with provincial data showing 14,189 were registered as of the end of March, earlier this year, up from 9,338 at the same point the previous year.

Advocates for EVs see the cars as a part of global efforts to reduce greenhouse gas emissions. Others are skeptical about their practicality and the cost of building the necessary infrastructure to support them.

Whether a Level 1 charger will work for drivers varies widely, said Electric Vehicle Association of Alberta board of directors president William York.

Extremely cold weather, bringing the temperature down in garages, as well as the size of electric trucks, create conditions that are more difficult for these lower-powered chargers to provide sufficient power, he said.

York noted there are electric vehicle energy management systems that can ensure Level 2 charges only work when a home's electrical panel is lightly loaded. But he also agreed that the ongoing research into charging EVs is responding to a real impediment to their uptake.

"It does seem apparent to us that researchers and boots on the ground are finding this to be more and more of a concern," York said.

"Especially as the demographic matures from the more DIY, affluent and technically savvy early customers, to the more mainstream consumers that just want a vehicle that gets them from A to B."